Transceivers and other radio devices, often referred to generally as “radios,” are used in a wide variety of contexts. In many cases, the radios are portable and are intended to be carried by a person, a vehicle, or other equipment from one place to another. Determining the exact location of a person or object associated with a particular radio can be important in some circumstances, and in some cases, finding the exact location within a specified area is critical. For example, for firefighters, knowing their exact location including floor of a multistory building can be a life or death situation.
Several methods are known for determining locations of radios. For example, a position can be obtained within a building using triangulation, and if the known positioned radios are placed properly, the position of the desired radio can be calculated. The main issue is that placing these radios is difficult since knowledge a priori of the general area is usually not known. To limit the number of radios involved would be of great value, but a precise calculation is critical. Alternatively, a satellite navigation system, such as GPS, may be used to determine the location of a GPS-equipped radio without any other radios being present. Unfortunately, although the (x,y) position of a GPS-equipped radio may be calculated reasonably accurately, GPS-based calculations of the z position are not very accurate. This leaves the user with the knowledge, for example, that the radio is a particular quadrant of a particular building, but the user does not know whether the radio is on the 1st floor or the 10th floor.